_Black_ is a well-behaved Unix-style command-line tool:
-- it does nothing if no sources are passed to it;
+- it does nothing if it finds no sources to format;
- it will read from standard input and write to standard output if `-` is used as the
filename;
- it only outputs messages to users on standard error;
-- exits with code 0 unless an internal error occurred (or `--check` was used).
+- exits with code 0 unless an internal error occurred or a CLI option prompted it.
## Usage
### Command line options
-_Black_ has quite a few knobs these days, although _Black_ is opinionated so style
-configuration options are deliberately limited and rarely added. You can list them by
-running `black --help`.
+The CLI options of _Black_ can be displayed by expanding the view below or by running
+`black --help`. While _Black_ has quite a few knobs these days, it is still opinionated
+so style options are deliberately limited and rarely added.
<details>
-<summary>Help output</summary>
+<summary>CLI reference</summary>
```{program-output} black --help
```console
$ black --version
-black, version 21.11b0
+black, version 22.8.0
```
An option to require a specific version to be running is also provided.
line-length = 88
target-version = ['py37']
include = '\.pyi?$'
+# 'extend-exclude' excludes files or directories in addition to the defaults
extend-exclude = '''
# A regex preceded with ^/ will apply only to files and directories
# in the root of the project.
-^/foo.py # exclude a file named foo.py in the root of the project (in addition to the defaults)
+(
+ ^/foo.py # exclude a file named foo.py in the root of the project
+ | .*_pb2.py # exclude autogenerated Protocol Buffer files anywhere in the project
+)
'''
```